Given that the examinee knows the answer to item i if and only if he knows the answer to both item g and item h, a "conjunctive" item response model is found such that items g, h, and i all have the same mathematical form of response function. Since such items may occur in practice, it is desirable that item response models satisfy this…

Methods for estimating the mean and variance of latent ability parameters of a normally distributed population that has been tested with Rasch model-calibrated test items are discussed. Methods for checking the normality of the population are also included. (JKS)

This paper describes a simulation that determines the adequacy of various indices as decision criteria for assessing unidimensionality. Using the sum of absolute residuals from the two-parameter latent trait model, indices were obtained that could discriminate between one latent trait and more than one latent trait. (Author/BW)

Two methods of constucting equal-interval scales for educational achievement are discussed: Thurstone's absolute scaling method and Item Response Theory. Alternative criteria for choosing a scale are contrasted. It is argued that clearer criteria are needed for judging the appropriateness and usefulness of alternative scaling procedures.…

The relationship between item parameter values obtained from independent Birnbaum (l968) model calibrations of the same item set from two different samples is examined. (Author)

Two of the most popular methods for obtaining equal-interval scales for educational measurement are discussed: Thurstone's method and Item Response Theory (IRT). Between-grade growth on these scales is compared; while unstandardized differences show different trends for the two scales, standardized differences that take standard deviations into…

A latent class model for handling the items in Birenbaum and Tatsuoka's study is described. A method to derive the optimal scoring rule when multiple choice test items are used is illustrated. Remedial training begins after a determination is made as to which of several erroneous algorithms is being used. (Author/DWH)

The purpose of this study is to present and illustrate the application of a general linear model for the analysis of test networks based on Rasch measurement models. Test networks can be used to vertically equate a set of tests which cover a wide range of difficulties. The criteria of coherence and consistency are proposed in order to assess the…

The accuracy of trait estimates obtained from three vertical equating methods was examined. The procedures studied included two anchor test designs and a single-group design. Data from two content areas and two grade combinations were studied. A three-parameter logistic model was used to perform the equatings. The results obtained were used to…

The first step of the data analysis with respect to the eventual application of the various new methods in latent trait theory is here initiated. The data are a set of approximately 500 item responses of each of 7,439 examinees to the Iowa Tests of Basic Skills, Form 6, on one of three difficulty levels, which correspond to the ages of 11, 12 and…

Rasch model equatings of multilevel achievement test data before and after the deletion of misfitting persons were compared. Rasch equatings were also compared with an equating obtained using the equipercentile method. No basis could be found in the results for choosing between the two Rasch equatings. (Author/LMO)

The symposium, "Taming the Rasch Tiger: Using Item Response Theory in Practical Educational Measurement," was organized to deemphasize the technical complexities of item response theory (IRT) and to show the audience how IRT can be used in practical educational measurement. Four papers from the symposium are summarized and comments are…

A comparison was made between four different scoring procedures for the 45-item Reading Comprehension subtest, Level I, of the Comprehensive Test of Basic Skills, Form S, for a sample of 1,000 third grade students. These students were selected to have been among those who omitted from 3 to 22 of the 45 items. Another representative sample of 1,300…

This study developed a hybrid of item response theory (IRT) models and latent class models, which combined the strengths of each type of model. The primary motivation for developing the new model is to describe characteristics of examinees' knowledge at the time of the examination. Hence, the application of the model lies mainly in so-called…

The purpose of this study was to compare the relative robustness of the one-, two-, and modified two-parameter latent trait logistic models for the Iowa Tests of Educational Development. Results suggest that the modified two-parameter model may provide the best representation of the data. (Author/BW)